Bone daggers from New Guinea. a) Human bone dagger attributed to the Upper Sepik River. b) Cassowary bone dagger attributed to the Abelam people. (Credit: Hood Museum of Art, Dartmouth College)Daggers made of human bone were regularly used in mortal combat in New Guinea, and now scientists find these weapons were specially engineered for strength so they could find repeated use in violent confrontations. Bone daggers were once widespread in New Guinea. The weapons were worn on men's upper arms, and were carved with elaborate inscriptions. However, they were more than just ornaments.